Systems and methods for protecting a turbomachine

ABSTRACT

Systems and methods for protecting a turbomachine may include a trip throttle valve having a throttle valve assembly and a trip valve assembly. The trip valve assembly may include a plurality of trip valves fluidly coupled to a hydraulic cylinder of the throttle valve assembly via a first flow path and a second flow path in parallel with one another. The trip valve assembly may also include a plurality of isolation valves fluidly coupled to the hydraulic cylinder via the first flow path and the second flow path. The plurality of isolation valves may be configured to selectively prevent fluid communication between the plurality of trip valves and the hydraulic cylinder to allow testing of one or more of the plurality of trip valves during operation of the turbomachine.

BACKGROUND

Steam turbines power plants typically utilize a trip throttle valve tocontrol the introduction of high pressure steam to the steam turbine.The trip throttle valve may be electrically coupled to a control systemcapable of monitoring certain conditions indicative of imminent dangerto the steam turbine, e.g., rotor overspeed. When such conditions aremet, the control system may send a signal to trip the steam turbine,thereby closing the trip throttle valve and preventing the inflow of thehigh pressure steam to the steam turbine. In order to ensure that thetrip throttle valve is in proper working condition, testing of the tripthrottle valve should be carried out on a regular basis. Infrequenttesting of the trip throttle valve may result in the accumulation ofscale or rust that may affect the ability of the trip throttle valve toproperly close after receiving the signal to trip. Accordingly, such amalfunction of the throttle trip valve may result in the inability tosafely shutdown the steam turbine in the event of a trip condition.

Traditionally, in order to test the trip throttle valve, the steamturbine is tripped, and thus, taken offline resulting in production andeconomic losses. Accordingly, such drawbacks have led to methods oftesting the trip throttle valve without taking the steam turbineoffline. For example, one such method includes utilizing a lockoutdevice to isolate trip components of the trip throttle valve to test thetrip components without tripping the steam turbine. However, such apractice may leave the steam turbine unprotected from a potential tripcondition arising during testing.

What is needed, therefore, is a trip throttle valve which may be testedduring operation of the steam turbine while providing for the safeshutdown of the steam turbine in the event of an occurrence of a tripcondition during testing.

SUMMARY

Embodiments of the disclosure may provide a trip throttle valve. Thetrip throttle valve may include a trip throttle valve inlet configuredto receive a flow of process fluid from a process fluid source, and atrip throttle valve outlet configured to fluidly communicate with aturbomachine. The trip throttle valve may also include a throttle valveassembly defining a throttle valve chamber in fluid communication withthe trip throttle valve inlet and the trip throttle valve outlet. Thethrottle valve assembly may be configured to control an amount of theprocess fluid flowing into the turbomachine. The throttle valve assemblymay include a valve seat disposed within the throttle valve chamber, anda valve head displaceable in the throttle valve chamber and configuredin an open position to allow the process fluid to flow into theturbomachine and in a closed position to seat in the valve seat toprevent the process fluid from flowing into the turbomachine. Thethrottle valve assembly may also include a piston connected to the valvehead via a valve stem, a biasing member disposed about the valve stemand configured to bias the piston in a first position such that thevalve head is seated in the valve seat, a hydraulic cylinder configuredto receive the piston and a hydraulic fluid therein, and an actuatorassembly fluidly coupled with the hydraulic cylinder. The actuatorassembly may be configured to transfer the hydraulic fluid to and fromthe hydraulic cylinder via a pressure differential across the piston.The trip throttle valve may also include a trip valve assemblyconfigured to selectively remove hydraulic pressure from the hydrauliccylinder. The trip valve assembly may include a plurality of trip valvesfluidly coupled to the hydraulic cylinder via a first flow path and asecond flow path. The plurality of trip valves may include a first tripvalve and a second trip valve arranged in fluid communication with afirst pressure relief valve in the first flow path, and a third tripvalve and a fourth trip valve arranged in fluid communication with asecond pressure relief valve in the second flow path. The first flowpath and the second flow path may be in parallel with one another. Thetrip valve assembly may also include a plurality of isolation valvesfluidly coupled to the hydraulic cylinder via the first flow path andthe second flow path. The plurality of isolation valves may include afirst isolation valve and a second isolation valve arranged in the firstflow path and configured to selectively prevent fluid communicationbetween the first trip valve and the second trip valve and the hydrauliccylinder, and a third isolation valve and a fourth isolation valvearranged in the second flow path and configured to selectively preventfluid communication between the third trip valve and the fourth tripvalve and the hydraulic cylinder.

Embodiments of the disclosure may further provide a protection systemfor a turbomachine. The protection system may include a trip throttlevalve. The trip throttle valve may include a throttle valve assemblyhaving a longitudinal axis and being configured to regulate a flow ofprocess fluid into the turbomachine. The throttle valve assembly mayinclude a piston disposed within a hydraulic cylinder and configured tobe axially displaced in the hydraulic cylinder based on an amount ofhydraulic fluid provided to the hydraulic cylinder. The trip throttlevalve may also include a trip valve assembly fluidly coupled to thehydraulic cylinder via a first flowpath and a second flowpath, the firstand second flowpath being in parallel with one another. The trip valveassembly may include a first isolation valve and a second isolationvalve disposed in the first flowpath. Each of the first isolation valveand the second isolation valve may be configured to selectively preventfluid communication between the first flowpath of the trip valveassembly and the hydraulic cylinder. The trip valve assembly may alsoinclude a third isolation valve and a fourth isolation valve disposed inthe second flowpath. Each of the third isolation valve and a fourthisolation valve may be configured to selectively prevent fluidcommunication between the second flowpath of the trip valve assembly andthe hydraulic cylinder. The trip valve assembly may further include afirst trip valve disposed in the first flowpath and interposed betweenthe first isolation valve and the second isolation valve. The trip valveassembly may further include a second trip valve disposed in the secondflowpath and interposed between the third isolation valve and the fourthisolation valve. The protection system may also include a control systemconfigured to monitor an operation of the turbomachine for a tripcondition during a testing of the trip valve assembly. The controlsystem may include a plurality of sensors communicatively coupled to theturbomachine and configured to detect one or more operating parametersof the turbomachine. The control system may also include a firstcontroller communicatively coupled to the plurality of sensors. Thefirst controller may include at least one processor configured toreceive at least one signal corresponding to at least one detectedoperating parameter of the turbomachine. The control system may alsoinclude a second controller communicatively coupled to the firstcontroller and the throttle valve assembly. The second controller mayinclude at least one processor configured to transmit at least oneinstruction to the throttle valve assembly to cause the piston to beaxially displaced in the hydraulic cylinder along the longitudinal axisbased on information received from the first controller.

Embodiments of the disclosure may further provide a method for testing atrip throttle valve during operation of a turbomachine. The method mayinclude flowing a process fluid through the trip throttle valve and intoan inlet of the turbomachine. The method may also include closing afirst isolation valve and retaining a second isolation valve in an openposition, where the first isolation valve and the second isolation valveare disposed in a first flowpath fluidly coupling a trip valve assemblyand a hydraulic cylinder of a the trip throttle valve. The method mayfurther include retaining in an opened position a third isolation valveand a fourth isolation valve disposed in a second flowpath fluidlycoupling the trip valve assembly and the hydraulic cylinder of the tripthrottle valve. The first flowpath and the second flowpath may be inparallel. The method may also include opening a first trip valvedisposed in the first flowpath and interposed between the firstisolation valve and the second isolation valve, such that the operationof the turbomachine is maintained. The method may further includedetecting a pressure in the first flowpath via a pressure sensor, thedetected pressure indicative of an operating condition of the first tripvalve.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying Figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale. In fact, the dimensions of the variousfeatures may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a schematic of an exemplary system for protecting oneor more components of a turbomachine, according to one or moreembodiments of the disclosure.

FIG. 2 illustrates a cross-sectional view of an exemplary trip throttlevalve, according to one or more embodiments of the disclosure.

FIG. 3 illustrates a schematic of an exemplary actuator assembly,according to one or more embodiments of the disclosure.

FIG. 4 illustrates a schematic of an exemplary trip valve assembly,according to one or more embodiments of the disclosure.

FIG. 5 illustrates a schematic of another exemplary trip valve assembly,according to one or more embodiments of the disclosure.

FIG. 6 is a flowchart depicting a method for testing a trip throttlevalve during operation of a turbomachine, according to one or moreembodiments of the disclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure describes severalexemplary embodiments for implementing different features, structures,or functions of the invention. Exemplary embodiments of components,arrangements, and configurations are described below to simplify thepresent disclosure; however, these exemplary embodiments are providedmerely as examples and are not intended to limit the scope of theinvention. Additionally, the present disclosure may repeat referencenumerals and/or letters in the various exemplary embodiments and acrossthe Figures provided herein. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various exemplary embodiments and/or configurationsdiscussed in the various Figures. Moreover, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed interposing the first and second features, suchthat the first and second features may not be in direct contact.Finally, the exemplary embodiments presented below may be combined inany combination of ways, i.e., any element from one exemplary embodimentmay be used in any other exemplary embodiment, without departing fromthe scope of the disclosure.

Additionally, certain terms are used throughout the followingdescription and claims to refer to particular components. As one skilledin the art will appreciate, various entities may refer to the samecomponent by different names, and as such, the naming convention for theelements described herein is not intended to limit the scope of theinvention, unless otherwise specifically defined herein. Further, thenaming convention used herein is not intended to distinguish betweencomponents that differ in name but not function. Additionally, in thefollowing discussion and in the claims, the terms “including” and“comprising” are used in an open-ended fashion, and thus should beinterpreted to mean “including, but not limited to.” All numericalvalues in this disclosure may be exact or approximate values unlessotherwise specifically stated. Accordingly, various embodiments of thedisclosure may deviate from the numbers, values, and ranges disclosedherein without departing from the intended scope. Furthermore, as it isused in the claims or specification, the term “or” is intended toencompass both exclusive and inclusive cases, i.e., “A or B” is intendedto be synonymous with “at least one of A and B,” unless otherwiseexpressly specified herein.

Systems and methods disclosed herein may protect one or more componentsof a turbomachine from damage that may occur in the event of certainconditions, such as, for example, low lubrication oil pressure, highrotor vibrations, rotor overspeed, and high bearing temperatures. Assuch conditions may indicate imminent danger to the turbomachine, thesystems and methods disclosed herein may protect the turbomachine fromdamage by tripping, or shutting down, the turbomachine on an emergencybasis. To ensure that the turbomachine may be reliably shutdown on anemergency basis, the systems and methods as disclosed herein allow forthe testing of the components involved in the shutdown of theturbomachine during the ordinary operation thereof, thereby avoidingtaking the turbomachine offline during the testing process and allowingfor the continued operation thereof while maintaining protection of theturbomachine in the event of a trip condition. By doing so, thedisruption or stoppage of the operation of the turbomachine duringtesting of the trip throttle valve may be avoided.

Turning now to the Figures, FIG. 1 illustrates a schematic of anexemplary system 100 for protecting one or more components of aturbomachine 102, according to one or more embodiments of thedisclosure. In one or more embodiments, the one or more components maybe or include a rotor (not shown) and/or rotary components thereof. Theturbomachine 102 may be a steam turbine configured to extract energyfrom a flow of steam provided thereto and to drive other processcomponents (not shown), such as, for example, a generator, a compressor,or a pump. Accordingly, the steam turbine may be part of a steam turbinepower plant further including a steam generator 104, e.g., a boiler,configured to convert feed water to the steam provided to the steamturbine. The steam turbine power plant may further include a condenser(not shown) configured to cool the steam exiting the steam turbine. Inan embodiment in which the steam turbine drives a generator, thegenerator may be electrically coupled to and configured to supply powerto an electrical grid or to other components (e.g., actuators, controlsystems, and sensors) of the steam turbine power plant.

As illustrated in FIG. 1, the system 100 may include a trip throttlevalve 106 having a trip throttle valve inlet 108 fluidly coupled to thesteam generator 104 via process piping 110, and a trip throttle valveoutlet 112 fluidly coupled to an inlet of the turbomachine via processpiping 114. Referring now to FIG. 2 with continued reference to FIG. 1,FIG. 2 illustrates an exemplary cross-sectional view of the tripthrottle valve 106, according to one or more embodiments of thedisclosure. The trip throttle valve 106 may include a throttle valveassembly 116 and a trip valve assembly 118. The flow of a process fluid,e.g., steam, to the turbomachine 102 may be regulated by the throttlevalve assembly 116 during ordinary operation of the turbomachine 102;thus, in the exemplary system 100, the throttle valve assembly 116 maybe fluidly coupled to and disposed downstream of a process fluid source,e.g., the steam generator 104, and upstream of the inlet of theturbomachine 102. Those of ordinary skill in the art will appreciatethat one or more process components may be interposed between the tripthrottle valve 106 and the process fluid source.

As illustrated most clearly in FIG. 2, the throttle valve assembly 116may include a longitudinal axis 200 and a valve body 202 defining athrottle valve chamber 204 in fluid communication with the trip throttlevalve inlet 108 and the trip throttle valve outlet 112, therebyselectively providing a flowpath from the steam generator 104, throughthe trip throttle valve 106, and to the turbomachine 102. The throttlevalve assembly 116 may include a valve seat 206 disposed within thethrottle valve chamber 204, and a valve head 208 axially displaceable inthe throttle valve chamber 204 along the longitudinal axis 200 andconfigured in an open position (as shown in FIG. 2) to allow the processfluid to flow into the turbomachine 102 and in a closed position to seatin the valve seat 206 to prevent the process fluid from flowing throughthe throttle valve chamber 204 and into the turbomachine 102.

The throttle valve assembly 116 may further include a piston 210 and avalve stem 212 interconnecting the valve head 208 and the piston 210.The valve stem 212 may be a single, unitary component extending from thevalve head 208 to the piston 210, or in other embodiments, the valvestem 212 may be formed from multiple segments coupled with one anothervia one or more couplings 214. The piston 210 may be slidably disposedin a hydraulic cylinder 216 of the throttle valve assembly 116 andbiased in a shutdown position by a biasing member 218, illustrated as aspring in FIG. 2, to thereby close the trip throttle valve 106, or urgedin an opposing direction along the longitudinal axis 200 of the throttlevalve assembly 116 to open the trip throttle valve 106. The throttling,e.g., the amount the trip throttle valve 106 is opened, may depend on apressure differential across the piston 210.

The biasing member 218 may be disposed in a spring housing 220 of thethrottle valve assembly 116 interconnecting the valve body 202 and thehydraulic cylinder 216. As illustrated in FIG. 2, the spring housing 220may be coupled to an intermediary housing 222 disposed between thespring housing 220 and the valve body 202. The intermediary housing 222may house one or more couplings 214 of the valve stem 212 which may beutilized to provide valve position information. In some embodiments, thespring housing 220 may be directly coupled to the valve body 202. Inother embodiments, the intermediary housing 222 may be part of orintegral with the valve body 202, as shown in FIG. 1.

In one or more embodiments, the biasing member 218 may be disposed aboutand concentric with the valve stem 212 in the spring housing 220, as thevalve stem 212 extends from the valve body 202 through the springhousing 220 and into the hydraulic cylinder 216. A first end portion ofthe biasing member 218 may be disposed on a retaining member 224illustrated as a spring perch in FIG. 2 and coupled to or integral withthe valve stem 212 within the spring housing 220. A second end portionof the biasing member 218 may be disposed against an end portion 226 ofthe spring housing 220 axially adjacent the intermediary housing 222.Accordingly, the biasing member 218 may be compressed by the travel ofthe retaining member 224 in an axial direction toward the valve seat206, as shown in FIG. 2.

The hydraulic cylinder 216 may define a cylinder chamber 228 a, 228 b inwhich the piston 210 may be slidably displaced along the longitudinalaxis 200 of the throttle valve assembly 116. The cylinder chamber 228 a,228 b may be configured to receive, retain, and/or discharge hydraulicfluid therefrom. In one or more embodiments, the hydraulic fluid may beoil. In another embodiment, the hydraulic fluid may be petroleum orwater-based oils. In another embodiment, the hydraulic fluid may bepetroleum or water-based hydraulic fluids. As disposed in the hydrauliccylinder 216, the piston 210 may separate the cylinder chamber 228 a,228 b into two sealed cylinder chambers sections axially opposing oneanother on opposing sides of the piston 210. As shown in FIG. 2, thepiston 210 may separate the hydraulic cylinder 228 a, 228 b into a firstcylinder chamber section 228 a and a second cylinder chamber section 228b, where the volume of each of the first and second cylinder chambersections 228 a, 228 b may be dependent on the axial position of thepiston 210 along the longitudinal axis 200 of the throttle valveassembly 116. The hydraulic fluid may be supplied from and/or returnedto an actuator assembly 120 of the throttle valve assembly 116. Ahousing 230 of the hydraulic cylinder 216 may define a pair of hydraulicfluid orifices 300 a, 300 b (most clearly seen in FIG. 3) at respectiveends 302, 304 (most clearly seen in FIG. 3) of the hydraulic cylinder216. Accordingly, the first cylinder chamber section 228 a and thesecond cylinder chamber section 228 b may fluidly communicate with theactuator assembly 120 via the respective hydraulic fluid orifices 300 a,300 b.

Referring now to FIG. 3 with continued reference to FIGS. 1 and 2, FIG.3 illustrates an exemplary schematic of the actuator assembly 120,according to one or more embodiments of the disclosure. The actuatorassembly 120 may be configured to regulate the axial position of thepiston 210 in the cylinder chamber 228 a, 228 b via the amount ofhydraulic fluid supplied to each of the first and second cylinderchamber sections 228 a, 228 b. To that end, the actuator assembly 120may include a pump 306 driven by a driver 308. The pump 306 may be areversible hydraulic pump capable of supplying hydraulic fluid to eachof the first and second cylinder chamber sections 228 a, 228 b and thusmay have an alternating suction side and discharge side depending on theoperation thereof. Accordingly, the pump 306 may be a positivedisplacement gear pump mounted about a rotary shaft 307 and configuredto rotate in either direction. In one or more embodiments, the driver308 may be a motor and more specifically may be an electric motor, suchas a permanent magnet motor, and may include a stator (not shown) and arotor (not shown). It will be appreciated, however, that otherembodiments may employ other types of electric motors including, but notlimited to, synchronous motors, induction motors, and brushed DC motors.The pump 306 may be configured to circulate the hydraulic fluid to andfrom the first and second cylinder chamber sections 228 a, 228 b in aclosed-loop configuration as shown in FIG. 3. By implanting aclosed-loop configuration, the hydraulic fluid in the actuator assembly120 may be isolated from the environment and immune to degradation as aresult of exposure to moisture and other atmospheric elements.

The actuator assembly 120 may further include a plurality of valves 310a-j configured to regulate the flow of the hydraulic fluid to the firstand second cylinder chamber sections 228 a, 228 b dependent on thedirection of operation of the pump 306. The plurality of valves 310 a-hmay include a flow match valve 310 a selectively fluidly coupling thepump 306 to the first cylinder chamber section 228 a, and a flow matchvalve 310 b selectively fluidly coupling the pump 306 to the secondcylinder chamber section 228 b. In addition, in one or more embodiments,the plurality of valves 310 a-h may include a check valve 310 cselectively fluidly coupling the pump 306 to the first cylinder chambersection 228 a, and a check valve 310 d selectively fluidly coupling thepump 306 to the second cylinder chamber section 228 b. In one or moreembodiments, either of the flow match valves 310 a, 310 b may includeone or more spool valves, cross port pilot-to-open check valves, and/orcross port counterbalance valves. In one or more embodiments, theactuator assembly 120 may also include a reservoir 318 configured tostore additional hydraulic fluid to supplement the actuator assembly 120with additional hydraulic fluid as needed based on thermal expansion.The pump 306 may be in fluid communication with the reservoir 318 viacheck valves 310 e and 310 f and may draw the additional hydraulic fluidinto the suction side thereof as necessitated by the thermal expansion.

The system 100 may further include a control system 122 configured tomonitor and control the operation of the turbomachine 102. Inparticular, the control system 122 may be configured to regulate theamount of process fluid flowing into the turbomachine 102 via the tripthrottle valve 106. Accordingly, as disclosed in the present disclosure,the trip throttle valve 106 may be referred to as an electro-hydraulictrip throttle valve. The control system 122 may include at least onecontroller (two shown 124 a, 124 b) including one or more processors 126configured to provide the processing capability to execute the operatingsystem, programs, interfaces, and any other functions of the controlsystem 122, one or more microprocessors and/or related chip sets, acomputer/machine readable memory capable of storing date, programinformation, or other executable instructions thereon, general purposemicroprocessors, special purpose microprocessors, or a combinationthereof, on board memory for caching purposes, instruction setprocessors, and so forth. Each processor 126 may operate independentlyor may communicate with at least one other processor 126. In one or moreembodiments, the control system 122 may include a plurality ofcontrollers 124 a, 124 b communicatively coupled with one another andthe turbomachine 102, where each controller 124 a, 124 b may include oneor more processors 126.

As shown in FIG. 1, the control system 122 may further include aplurality of sensors 128 communicatively coupled to one or more of theprocessors 126 of the controller 124 a and configured to detect one ormore operating parameters of the turbomachine 102. In one or moreembodiments, at least one of the sensors 128 may be a toothed wheel orgear to sense rotor speed of the turbomachine 102. In other embodiments,the sensors 128 may be or include temperature sensors, pressure sensors,flow rate sensors, or any other sensors configured to measure anoperating parameter of the turbomachine 102, the process fluid flowingtherethrough, or parameters from other components in the system 100,such as temperatures, pressures, rotation speed, frequency, voltage,etc. In addition, the plurality of sensors 128 may include a positionfeedback sensor 232 configured to determine the position of the piston210 via the position of the valve stem 212. The sensors 128 may bewirelessly connected or may be connected via cable 130 to the controller124 a to transmit signals corresponding to the detected operatingparameters to the controller 124 a for processing. The position feedbacksenor 232 may be wirelessly connected or may be connected via cable 132to the controller 124 b and relayed to the controller 124 a to transmitsignals corresponding to the detected position of the piston 210 forprocessing. The controller 124 a may process, via the one or moreprocessors 126, the received signals corresponding to the detectedposition of the piston 210 and/or operating parameters of theturbomachine 102 received via the controller 124 a and may transmitcorresponding signals to the controller 124 b for processing. Thecontroller 124 b may transmit corresponding signals to the actuatorassembly 120 responsive to the desired piston positon 210 and/oroperating parameters in view of the received operating parameters fromthe sensors 128 and 232 and the controller 124 a. The signals may beprovided to the pump 306 via cable 134 to pressurize one of the flowmatch valves 310 a, 310 b to maintain or axially displace the piston 210accordingly.

Turning now to an exemplary method of operating the trip throttle valve106 to regulate the flow of process fluid to the turbomachine 102 duringthe ordinary operation of the turbomachine 102, one or more of thesensors 128 are communicatively coupled to the turbomachine 102 anddetect one or more operating parameters thereof, such as the rotor speedof the turbomachine 102. The detected operating parameter(s) is/aretransmitted via the one or more sensors 128 to the controller 124 a,where the operating parameters are processed via the one or moreprocessors 126 and a determination is made to increase the flowrate ofthe process fluid entering the turbomachine 102, decrease the flowrateof the process fluid entering the turbomachine 102, or maintain theflowrate of the process fluid entering the turbomachine 102. A signalincluding the appropriate instructions is sent to the controller 124 b,which processes the signal and relays a corresponding signal to the pump306 of the actuator assembly 120. In some embodiments, the signal oranother signal is sent to the driver 308 in addition to the pump 306.The driver 308 is activated to drive the pump 306 in order to pressurizeeither the first cylinder chamber section 228 a or the second cylinderchamber section 228 b dependent on the instruction(s) received by thepump 306 from the controller 124 b.

In the event of an instruction to decrease the flowrate of process fluidentering the turbomachine 102, the pump 306 is activated to circulatehydraulic fluid into the second cylinder chamber section 228 b viahydraulic fluid orifice 300 b by pressurizing port 320. Accordingly, theflow match valve 310 a becomes unbalanced by the pressure differentialand is axially displaced, thereby lifting the check valve 310 c andopening port 322 to port 324, and port 320 to port 326. The pressurizedhydraulic fluid may flow through port 326 and conduit 328 to port 330and port 332 to the second cylinder chamber section 228 b via conduit334. As the actuator assembly 120 is a closed loop configuration, thesame amount of hydraulic fluid entering the second cylinder chambersection 228 b is removed from the first cylinder chamber section 228 a.Thus, the same amount of hydraulic fluid is removed from the firstcylinder chamber section 228 a via hydraulic fluid orifice 300 a and thepiston 210 moves axially toward the end 302 of the hydraulic cylinder216. As the valve head 208 is interconnected with the piston 210 via thevalve stem 212, the valve head 208 is moved axially toward the valveseat 206, thereby decreasing the flowpath for the process fluid to flowinto the turbomachine 102, and thus, decreasing the flow of processfluid into the turbomachine 102. The hydraulic fluid exiting the firstcylinder chamber section 228 a via the hydraulic fluid orifice 300 aflows via conduit 336 through the port 322 and the check valve 310 i andinto the port 324 and enters the suction side of the pump 306 viaconduit 338.

In the event of an instruction to increase the flowrate of process fluidentering the turbomachine 102, the pump 306 is activated to circulatehydraulic fluid into the first cylinder chamber section 228 a viahydraulic fluid orifice 300 a by pressurizing pressurize port 340.Accordingly, the flow match valve 310 b becomes unbalanced by thepressure differential and is axially displaced, thereby lifting thecheck valve 310 d and thereby opening the port 332 to port 342, and theport 340 to port 344. The pressurized hydraulic fluid may flow throughport 344 and conduit 346 to port 348 and port 322 to the first cylinderchamber section 228 a via conduit 336. As the actuator assembly 120 is aclosed loop configuration, the same amount of hydraulic fluid enteringthe first cylinder chamber section 228 a is removed from the secondcylinder chamber section 228 b. Thus, the same amount of hydraulic fluidis removed from the second cylinder chamber section 228 b via hydraulicfluid orifice 300 b and the piston 210 moves axially toward the end 304of the hydraulic cylinder 216. As the valve head 208 is interconnectedwith the piston 210 via the valve stem 212, the valve head 208 is movedaxially away the valve seat 206, thereby increasing the flowpath for theprocess fluid to flow into the turbomachine 102, and thus, increasingthe flow of process fluid into the turbomachine 102. The hydraulic fluidexiting the second cylinder chamber section 228 b via the hydraulicfluid orifice 300 b flows via conduit 334 through the port 332 and thecheck valve 310 j and into the port 342 and enters the suction side ofthe pump 306 via conduit 354.

In the event of an instruction to maintain the flowrate of the processfluid entering the turbomachine 102, the pump 306 is deactivated andboth check valves 310 c and 310 d close. The hydraulic fluid may thus belocked within the hydraulic cylinder 216, thereby maintaining thepressure differential across the piston 210 such that the piston 210remains in a fixed position. Accordingly, the valve head 208 remains ina fixed position, thereby maintaining the current flowrate. When lockedin place, the hydraulic cylinder 216 and hydraulic fluid may be subjectto expansion due to thermal expansion. Accordingly, the actuatorassembly may further include relief valves 352 and 354 to protect theactuator assembly from overpressure generated by thermal expansion. Asillustrated in FIG. 3, the pressure relief valves 352 and 354 may befluidly coupled to the reservoir 318 to return any bled-off hydraulicfluid thereto. As may be understood by those of skill in the art, thepressure differential across the piston 210 may move the piston 210axially toward either end 302, 304 of the hydraulic cylinder 216. Suchmovement of the piston 210 causes the attached valve head 208 to beaxially displaced in relation to the valve seat 206, thereby throttlingthe trip throttle valve 106.

In one or more embodiments, the trip throttle valve 106 may furtherinclude a solenoid valve 350 fluidly coupled with the hydraulic cylinder216 and configured to exercise or test the trip throttle valve 106 byactuating the trip throttle valve 106 to a set point (for example,seventy-five percent open) and then returning the trip throttle valve106 to a fully-opened position to ensure that the trip throttle valve106 is functioning and has not frozen in place. To that end, thesolenoid valve 350 may be cross ported across the hydraulic cylinder 216as shown in FIG. 3. The solenoid valve 350 may be communicativelycoupled to the controller 124 a and/or controller 124 b. The controller124 b may be programmed to periodically instruct the solenoid valve 350to actuate the trip throttle valve 106 to ensure the ordinary operationthereof. In an exemplary operation thereof, the controller 124 btransmits an instruction to the solenoid valve 350, which allows thetrip throttle valve 106 to be moved to a predetermined position and thenreturned to the fully-opened position, thereby validating that the tripthrottle valve 106 is operational and is not frozen in place.

As noted above, the system 100 may protect the turbomachine 102 fromdamage by shutting the turbomachine 102 down on an emergency basis. Tothat end, as shown in FIG. 1 and as noted above, the trip throttle valve106 may further include the trip valve assembly 118. The trip valveassembly 118 may be configured to trip or shutdown the turbomachine 102in the event one or more of the sensors 128 detects an operatingparameter of the turbomachine 102 indicative of imminent danger to theoperability of the turbomachine 102. Referring now to FIG. 4 withcontinued reference to FIGS. 1-3, FIG. 4 illustrates an exemplaryschematic of the trip valve assembly 118, according to one or moreembodiments of the disclosure. The trip valve assembly 118 may include aplurality of trip valves 400 a-d fluidly coupled to the hydrauliccylinder 216 via trip flowpaths 402 and 404 and conduits 405 and 407. Inone or more embodiments, one or more of the trip valves 400 a-d may besolenoids. In other embodiments, each of the trip valves 400 a-d may bea solenoid. As shown in FIG. 4, the plurality of trip valves 400 a-d mayinclude a trip valve 400 a and a trip valve 400 b arranged in fluidcommunication with one another in the flowpath 402, and a trip valve 400c and a trip valve 400 d arranged in fluid communication with oneanother in the flowpath 404. The flowpath 402 and the flowpath 404 maybe in parallel with one another. Each of the trip valves 400 a-d may becommunicatively coupled to the controller 124 b via respective lines 409a-d and energized in a closed position during ordinary operation of theturbomachine 102.

As arranged in the system 100, the trip valves 400 a-d may be energizedin a closed position during ordinary operating conditions of theturbomachine 102. In the event of the detection of a fault parameter,i.e., a parameter indicative of imminent danger to the turbomachine 102,by the one or more sensors 128, the controller 124 b may transmit afault signal to the plurality of trip valves 400 a-d via lines 409 a-dto de-energize the trip valves 400 a-d. In the event a fault signal istransmitted to the trip valves 400 a-d, the trip valves 400 a-d may bedeenergized and opened to fluidly couple the first cylinder chambersection 228 a and the second cylinder chamber section 228 b, therebyallowing the biasing member 218 to force the piston 210 toward the end302 of the hydraulic cylinder 216, thereby seating the valve head 208 inthe valve seat 206 and shutting off the flow of the process fluid intothe turbomachine 102 and thus shutting down the operation of theturbomachine 102. As arranged, the trip throttle valve 106 may trip in0.3 seconds or less, and thus meets API 612 industrial standards.

As disclosed above, the system 100 allows for the testing of theemergency shutdown of the turbomachine 102 during the ordinary operationthereof, thereby avoiding taking the turbomachine 102 offline during thetesting process and allowing for the continued operation thereof whilemaintaining protection of the turbomachine 102 in the event of a tripcondition. To that end, the trip valve assembly 118 may further includea plurality of isolation valves 410 a-d fluidly coupled to the hydrauliccylinder 216 via the flowpaths 402 and 404 and conduits 405 and 407. Asarranged, the plurality of isolation valves 410 a-d are configured toisolate either of the flowpaths 402, 404 to allow for testing of thetrip valves 400 a, 400 b or 400 c, 400 d in the associated flowpath 402or 404 while allowing the trip valves 400 a, 400 b or 400 c, 400 d inthe other flowpath 402 or 404 the ability to trip as needed duringcontinued operation of the turbomachine 102, thus protecting theturbomachine 102 from damage. Accordingly, the turbomachine 102 may bemaintained in service during the testing of the trip valve assembly 118without being susceptible to damage if a trip condition were to occurduring testing of the trip valve assembly 118.

In one or more embodiments, one or more of the isolation valves 410 a-dmay be manually operated valves. In another embodiment, one or more ofthe isolation valves 410 a-d may be remotely-operated valves. In one ormore embodiments, each of the isolation valves 410 a-d may be a ballvalve; however, other valves such as poppet valves, gate valves, or thelike may be utilized without departing from the scope of thisdisclosure. The plurality of isolation valves 410 a-d may include twoisolation valves, isolation valve 410 a and isolation valve 410 b,arranged in the flowpath 402 and configured to prevent fluidcommunication between trip valves 400 a, 400 b and the hydrauliccylinder 216. The plurality of isolation valves 410 a-d may also includetwo isolation valves, isolation valve 410 c and isolation valve 410 d,arranged in the flowpath 404 and configured to prevent fluidcommunication between the trip valves 400 c, 400 d and the hydrauliccylinder 216.

As shown in FIG. 4, each pair of isolation valves 410 a-d in therespective flowpath 402, 404 may be disposed therein such that therespective pair of trip valves 400 a-d may be selectively prevented fromfluidly communicating with the hydraulic cylinder 216 via conduits 405and 407. Thus, for example, at least one of the isolation valves 410 a,410 b in the flowpath 402 may be closed thereby allowing the trip valves400 a, 400 b in the flowpath 402 to open during testing without shuttingdown the turbomachine 102. In addition, the other isolation valves 410c, 410 d in the flowpath 404 may remain open so that the other set oftrip valves 400 c, 400 d may be fluidly coupled to the hydrauliccylinder 216 via conduits 405 and 407 during testing to trip as neededin the event of a trip condition.

The trip valve assembly 118 may further include a plurality of pressurerelief valves 406 a, 406 b, each pressure relief valve 406 a, 406 bfluidly coupling the respective flowpaths 402, 404 with the reservoir318 and configured to control the respective pressures in the flowpaths402, 404 during testing of the trip valves 400 a-d. Each of the pressurerelief valves 406 a, 406 b may be fluidly coupled to respective flowcontrol orifices 412 a, 412 b. In addition, the trip valve assembly 118may further include additional flow control orifices 412 b and 412 dfluidly coupled to the respective flowpaths 402, 404 and the reservoir318. The flow control orifices 412 a-d may be configured to reduce theflow of the hydraulic fluid exiting the trip valve assembly 118 andminimizing movement of the piston 210 during the testing process. Eachof the flow control orifices 412 a-d may be fluidly coupled to arespective filter (not shown) to reduce clogging of the flow controlorifices 412 a-d.

The trip valve assembly 118 may further include a plurality of sensors414 a, 414 b. Each of the sensors 414 a, 414 b may be pressuretransducers and may be configured to validate that the trip valves 400a-d have changed state (i.e., opened or closed) and are functioningproperly. The trip valve assembly 118 may also include isolation valves416 a and 416 b capable of isolating respective flow lines 418 a and 418b from the reservoir 318. Closing isolation valves 416 a, 410 a, and 410b may isolate all components located in the flowpath 402 to therebyallow for the removal and replacement of any trip valve assemblycomponents (e.g., malfunctioning trip valves 400 a-d) in the flowpath402 without interrupting operation of the turbomachine 102 orcompromising the trip capability. Likewise, closing isolation valves 416b, 410 c and 410 d isolate all components located in the flow path 404to thereby allow for the removal and replacement of any trip valveassembly components (e.g., malfunctioning trip valves 400 c-d) in theflow path 404 without interrupting operation of the turbomachine 102 orcompromising the trip capability.

Referring now to FIG. 5, illustrates a schematic of another exemplarytrip valve assembly 500, according to one or more embodiments of thedisclosure. The trip valve assembly 500 may be similar in some respectsto the trip valve assembly 118 described above and thus may be bestunderstood with reference to FIGS. 1-4, where like numerals designatelike components and will not be described again in detail. As shown inFIG. 5, the trip valve assembly 500 may further include a two-position,three-way solenoid valves 502 a-d, each two-position, three-way solenoidvalve 502 a-d fluidly coupled with a respective trip valve 400 a-d. Inthe embodiment of FIG. 5, each trip valve 400 a-d is a pilot to closecheck valve. Each of the two-position, three-way solenoid valves 502 a-dmay be fluidly coupled with the reservoir 318 via line 418 a and line418 b. The actuation of each of the trip valves 400 a-d may becontrolled by the operation of the respective two-position, three-waysolenoid valves 502 a-d, thereby permitting testing and operation of thetrip throttle valve 106 in larger flowrate turbomachines 102.

Turning now to an exemplary method for testing the trip throttle valve106 during operation of the turbomachine 102, it will be appreciatedthat either pair of the trip valves 400 a, 400 b or 400 c, 400 d may betested. For the sake of brevity, the method of testing trip valves 400c, 400 d will be discussed below; however, the method of testing tripvalves 400 a, 400 b may be carried out in a similar manner. The methodmay include flowing a process fluid through the trip throttle valve 106and into an inlet of the turbomachine 102. In the flowpath 404, theisolation valve 410 d is closed and the other isolation valve 410 c inthe flowpath 404 is retained in an open position. In the flowpath 402,the isolation valves 410 a and 410 b are retained in an open position.The trip valve 400 c is de-energized and thus opened. A pressure isdetected in sensor 414 b and compared to a pressure value indicative ofthe trip valve 400 c being opened. If the detected pressure isindicative of the trip valve 400 d being opened, the trip valve 400 c isenergized and thus closed. A pressure is detected in sensor 414 b andcompared to a pressure value indicative of the trip valve 400 c beingclosed.

If the detected pressure is indicative of the trip valve 400 c beingclosed, the trip valve 400 d is de-energized and thus opened. A pressureis detected in sensor 414 b and compared to a pressure value indicativeof the trip valve 400 d being opened. If the detected pressure isindicative of the trip valve 400 d being opened, the trip valve 400 d isenergized and thus closed and the trip valve 400 c is de-energized againand thus re-opened. A pressure is detected in sensor 414 b and comparedto a pressure value indicative of the trip valve 400 c being re-opened.If the detected pressure is indicative of the trip valve 400 c beingre-opened, the trip valve 400 c is energized and thus closed. A pressureis detected in sensor 414 b and compared to a pressure value indicativeof the trip valve 400 c being closed. If the detected pressure isindicative of the trip valve 400 c being closed, it is determined thatthe trip valves 400 c, 400 d are in good working condition and testingmay be carried out on trip valves 400 a, 400 b if desired.

FIG. 6 is a flowchart depicting another exemplary method 600 for testinga trip throttle valve during operation of a turbomachine, according toone or more embodiments of the disclosure. The method 600 may includeflowing a process fluid through the trip throttle valve and into aninlet of the turbomachine, as at 602. The method 600 may also includeclosing a first isolation valve and retaining a second isolation valvein an open position, the first isolation valve and the second isolationvalve disposed in a first flowpath fluidly coupling a trip valveassembly and a hydraulic cylinder of a the trip throttle valve, as at604. The method 600 may further include retaining in an opened positiona third isolation valve and a fourth isolation valve disposed in asecond flowpath fluidly coupling the trip valve assembly and thehydraulic cylinder of a the trip throttle valve, the first flowpath andthe second flowpath being in parallel, as at 606. The method 600 mayalso include opening a first trip valve disposed in the first flowpathand interposed between the first isolation valve and the secondisolation valve, such that the operation of the turbomachine ismaintained, as at 608. The method 600 may further include detecting apressure in the first flowpath via a pressure sensor, the detectedpressure indicative of an operating condition of the first trip valve,as at 610.

The foregoing has outlined features of several embodiments so that thoseskilled in the art may better understand the present disclosure. Thoseskilled in the art should appreciate that they may readily use thepresent disclosure as a basis for designing or modifying other processesand structures for carrying out the same purposes and/or achieving thesame advantages of the embodiments introduced herein. Those skilled inthe art should also realize that such equivalent constructions do notdepart from the spirit and scope of the present disclosure, and thatthey may make various changes, substitutions and alterations hereinwithout departing from the spirit and scope of the present disclosure.

We claim:
 1. A trip throttle valve, comprising: a trip throttle valveinlet configured to receive a flow of process fluid from a process fluidsource; a trip throttle valve outlet configured to fluidly communicatewith a turbomachine; a throttle valve assembly defining a throttle valvechamber in fluid communication with the trip throttle valve inlet andthe trip throttle valve outlet, the throttle valve assembly configuredto control an amount of the process fluid flowing into the turbomachine,and the throttle valve assembly comprising a valve seat disposed withinthe throttle valve chamber; a valve head displaceable in the throttlevalve chamber and configured in an open position to allow the processfluid to flow into the turbomachine and in a closed position to seat inthe valve seat to prevent the process fluid from flowing into theturbomachine; a piston connected to the valve head via a valve stem; abiasing member disposed about the valve stem and configured to bias thepiston in a first position such that the valve head is seated in thevalve seat; a hydraulic cylinder configured to receive the piston and ahydraulic fluid therein; and an actuator assembly fluidly coupled withthe hydraulic cylinder, the actuator assembly configured to transfer thehydraulic fluid to and from the hydraulic cylinder via a pressuredifferential across the piston; and a trip valve assembly configured toselectively remove hydraulic pressure from the hydraulic cylinder, thetrip valve assembly comprising a plurality of trip valves fluidlycoupled to the hydraulic cylinder via a first flow path and a secondflow path, the plurality of trip valves comprising a first trip valveand a second trip valve arranged in fluid communication with a firstpressure relief valve in the first flow path; and a third trip valve anda fourth trip valve arranged in fluid communication with a secondpressure relief valve in the second flow path, the first flow path andthe second flow path being in parallel with one another; and a pluralityof isolation valves fluidly coupled to the hydraulic cylinder via thefirst flow path and the second flow path, the plurality of isolationvalves comprising a first isolation valve and a second isolation valvearranged in the first flow path and configured to selectively preventfluid communication between the first trip valve and the second tripvalve and the hydraulic cylinder; and a third isolation valve and afourth isolation valve arranged in the second flow path and configuredto selectively prevent fluid communication between the third trip valveand the fourth trip valve and the hydraulic cylinder.
 2. The tripthrottle valve of claim 1, wherein one or more trip valves of theplurality of trip valves are pilot-to-close check valves.
 3. The tripthrottle valve of claim 1, wherein one or more isolation valves of theplurality of isolation valves are manually-operated valves.
 4. The tripthrottle valve of claim 1, wherein the actuator assembly furthercomprises a pump fluidly coupled to the hydraulic cylinder in a closedloop configuration and configured to circulate the hydraulic fluid inthe closed loop configuration.
 5. The trip throttle valve of claim 4,wherein the hydraulic cylinder defines a cylindrical chamber in whichthe piston is disposed, wherein the piston separates the cylindricalchamber into a first cylindrical chamber section and a secondcylindrical chamber section.
 6. The trip throttle valve of claim 5,wherein the pump is reversible such that the pump may supply hydraulicfluid to either the first cylinder chamber section or the secondcylinder chamber section.
 7. The trip throttle valve of claim 6, whereinthe actuator assembly further comprises: a driver operatively coupled tothe pump and configured to drive the pump in a first rotationaldirection to supply the hydraulic fluid to the first cylinder chambersection and a second rotational direction to supply the hydraulic fluidto the second cylinder chamber section; and a reservoir fluidly coupledto a suction side of the pump and configured to store additionalhydraulic fluid.
 8. The trip throttle valve of claim 1, wherein: thebiasing member is a spring disposed in a spring housing coupled to thehydraulic cylinder and compressible based on an amount of hydraulicfluid provided to the first cylinder chamber section; and the firstpressure relief valve is fluidly coupled with a reservoir via a flowcontrol orifice.
 9. The trip throttle valve of claim 1, wherein thefirst pressure relief valve and the second pressure relief valve are influid communication with a reservoir.
 10. A protection system for aturbomachine, comprising: a trip throttle valve comprising a throttlevalve assembly having a longitudinal axis and being configured toregulate a flow of process fluid into the turbomachine, the throttlevalve assembly comprising a piston disposed within a hydraulic cylinderand configured to be axially displaced in the hydraulic cylinder basedon an amount of hydraulic fluid provided to the hydraulic cylinder; atrip valve assembly fluidly coupled to the hydraulic cylinder via afirst flowpath and a second flowpath, the first and second flowpathbeing in parallel with one another, and the trip valve assemblycomprising a first isolation valve and a second isolation valve disposedin the first flowpath, each of the first isolation valve and the secondisolation valve configured to selectively prevent fluid communicationbetween the first flowpath of the trip valve assembly and the hydrauliccylinder; a third isolation valve and a fourth isolation valve disposedin the second flowpath, each of the third isolation valve and a fourthisolation valve configured to selectively prevent fluid communicationbetween the second flowpath of the trip valve assembly and the hydrauliccylinder; a first trip valve disposed in the first flowpath andinterposed between the first isolation valve and the second isolationvalve; and a second trip valve disposed in the second flowpath andinterposed between the third isolation valve and the fourth isolationvalve; a control system configured to monitor an operation of theturbomachine for a trip condition during a testing of the trip valveassembly, the control system comprising a plurality of sensorscommunicatively coupled to the turbomachine and configured to detect oneor more operating parameters of the turbomachine; a first controllercommunicatively coupled to the plurality of sensors, the firstcontroller comprising at least one processor configured to receive atleast one signal corresponding to at least one detected operatingparameter of the turbomachine; and a second controller communicativelycoupled to the first controller and the throttle valve assembly, thesecond controller comprising at least one processor configured totransmit at least one instruction to the throttle valve assembly tocause the piston to be axially displaced in the hydraulic cylinder alongthe longitudinal axis based on information received from the firstcontroller.
 11. The protection system of claim 10, wherein the secondcontroller is communicatively coupled to the trip valve assembly andconfigured to actuate at least one trip valve of the plurality of tripvalves upon detection of a fault signal received by the first controllerand indicative of imminent danger to the turbomachine.
 12. Theprotection system of claim 11, wherein the plurality of sensors areconfigured to transmit the fault signal to the first controller.
 13. Theprotection system of claim 10, wherein the hydraulic cylinder defines acylindrical chamber in which the piston is disposed, wherein the pistonseparates the cylindrical chamber into a first cylindrical chambersection and a second cylindrical chamber section.
 14. The protectionsystem of claim 13, wherein the actuator assembly further comprises apump fluidly coupled to the hydraulic cylinder in a closed loopconfiguration and configured to circulate the hydraulic fluid in theclosed loop configuration.
 15. The protection system of claim 14,wherein the pump is reversible such that the pump may supply hydraulicfluid to either the first cylinder chamber section or the secondcylinder chamber section.
 16. A method for testing a trip throttle valveduring operation of a turbomachine, comprising: flowing a process fluidthrough the trip throttle valve and into an inlet of the turbomachine;closing a first isolation valve and retaining a second isolation valvein an open position, the first isolation valve and the second isolationvalve disposed in a first flowpath fluidly coupling a trip valveassembly and a hydraulic cylinder of a the trip throttle valve;retaining in an opened position a third isolation valve and a fourthisolation valve disposed in a second flowpath fluidly coupling the tripvalve assembly and the hydraulic cylinder of the trip throttle valve,the first flowpath and the second flowpath being in parallel; opening afirst trip valve disposed in the first flowpath and interposed betweenthe first isolation valve and the second isolation valve, such that theoperation of the turbomachine is maintained; and detecting a pressure inthe first flowpath via a pressure sensor, the detected pressureindicative of an operating condition of the first trip valve.
 17. Themethod of claim 16, further comprising comparing the detected pressureto a predetermined pressure in a processor of a controllercommunicatively coupled to the trip valve assembly, the predeterminedpressure indicative of the first trip valve being in an open position.18. The method of claim 17, further comprising: closing the first tripvalve; detecting a second pressure in the first flowpath via thepressure sensor, the detected second pressure indicative of an operatingcondition of the first trip valve; comparing the detected secondpressure to a second predetermined pressure in the processor of thecontroller communicatively coupled to the trip valve assembly, thesecond predetermined pressure indicative of the first trip valve beingin a closed position; opening a second trip valve disposed in the firstflowpath and interposed between the first isolation valve and the secondisolation valve, such that the operation of the turbomachine ismaintained; detecting a third pressure in the first flowpath via thepressure sensor, the detected third pressure indicative of an operatingcondition of the second trip valve; and comparing the detected thirdpressure to a third predetermined pressure in the processor of thecontroller communicatively coupled to the trip valve assembly, thesecond predetermined pressure indicative of the second trip valve beingin an open position.
 19. The method of claim 18, further comprising:closing the second trip valve; opening the first trip valve, such thatthe operation of the turbomachine is maintained; detecting a fourthpressure in the first flowpath via the pressure sensor, the detectedfourth pressure indicative of an operating condition of the first tripvalve; comparing the fourth detected pressure to a fourth predeterminedpressure in the processor of the controller communicatively coupled tothe trip valve assembly, the fourth predetermined pressure indicative ofthe first trip valve being in an open position; closing the first tripvalve, such that the operation of the turbomachine is maintained;detecting a fifth pressure in the first flow path via the pressuresensor, the detected fifth pressure indicative of an operating conditionof the first trip valve; comparing the fifth detected pressure to afifth predetermined pressure in the processor of the controllercommunicatively coupled to the trip valve assembly, the fifthpredetermined pressure indicative of the first trip valve being in aclosed position; and generating a signal in the controller indicative ofthe trip throttle valve being operational.
 20. The method of claim 19,wherein: at least one of the first isolation valve, the second isolationvalve, the third isolation valve, and the fourth isolation valve is amanually operated valve; each of the first trip valve and the secondtrip valve is a solenoid; and each of the first flow path and the secondflow path is fluidly coupled to a reservoir via a respective pressurerelief valve.